1. Field of the Invention
The present invention relates to a presentation device for capturing documents and displaying them on an external monitor or the like.
2. Description of the Related Art
With most presentation devices to date, separate control buttons were provided for adjusting zoom depending on zoom direction, i.e. one for the telephoto end and one for the wide end. In order to adjust zoom in the document presentation device, it was necessary to perform operations while verifying the location of each control button.
With respect to zoom control design, Japanese Patent Laid-Open Gazette 2002-333660A teaches technology relating to a still camera furnished with a jog dial. The cited publication teaches performing zoom operations by rotating the jog dial, with the zoom direction switched depending on the direction of rotation. With such a jog dial, zoom operation to the telephoto end and zoom operation to the wide end can be accomplished with a single control element, making it unnecessary to verify the locations of multiple buttons, as with the prior art.
In a compact type still camera, the zoom factor is typically about 2-3×, so the operation of rotating the jog dial is not especially difficult for the user, even when zooming from the wide end to the telephoto end. More recent presentation devices, however, have zoom factors as high as 10-20×, making it necessary in some instances to have to continuously rotate the jog dial several turns in order to reach the desired factor, as a result of which user convenience may suffer.